add :server_settings to pass options to :server, merges sinatra#431

Signed-off-by: Konstantin Haase <konstantin.mailinglists@googlemail.com>

lib/sinatra/base.rb

@@ -1351,9 +1351,10 @@ def quit!(server, handler_name)
       # with the constructed handler once we have taken the stage.
       def run!(options={})
         set options
-        handler      = detect_rack_handler
-        handler_name = handler.name.gsub(/.*::/, '')
-        handler.run self, :Host => bind, :Port => port do |server|
+        handler         = detect_rack_handler
+        handler_name    = handler.name.gsub(/.*::/, '')
+        server_settings = settings.respond_to?(:server_settings) ? settings.server_settings : {}
+        handler.run self, server_settings.merge(:Port => port, :Host => bind) do |server|
           unless handler_name =~ /cgi/i
             $stderr.puts "== Sinatra/#{Sinatra::VERSION} has taken the stage " +
             "on #{port} for #{environment} with backup from #{handler_name}"